The overall objective of the application is the evaluation of the role of oxidative stress in the development of human senile cataract. The application will study formation of nuclear cataract in a guinea pig model for nuclear cataract formation in aging humans. The guinea pig forms a nuclear cataract in response to hyperbaric oxygen. Traditional techniques such as Raman spectroscopy and 2-dimensional gel electrophoresis, SDS PAGE and immunoblot analyses will be combined with more innovative methods such as LC assays for disulfide bonds pioneered for lens proteins by Dr. M. Lou, a collaborator. The analyses will provide information on the relative contribution of membrane-associated aggregation and soluble crystallin aggregation to opacification in nuclear cataract of the hyperbaric oxygen/guinea pig model. While elements of the application such as the studies with knockout and transgenic animals may be premature, the application is generally very strong and important new information on cataract formation can be expected.